An amount of fuel consumed by a vehicle such a ship changes in accordance with a distance traveled, speed of travel and the like by the ship. To minimize an amount of fuel consumed by a vehicle such as a ship and thereby restrain costs, it is necessary to understand causes of any increase or decrease in fuel consumption of the vehicle.
JP2010-267184A discloses a technology that meets the object stated above. Specifically, JP2010-267184A discloses a technique for calculating an influence of factors pertaining to fuel expenses over a prescribed period of time, and calculating a cost difference between fuel expenses when one factor is replaced by another factor operative within a prescribed period of time, whereby a comparison of the influence of such factors can be evaluated in an effect on fuel consumption of a vehicle, such as a ship. In this instance, the term “factors” used in relation to fuel expenses are: fuel consumption; unit fuel price; and speed of travel.
Generally a voyage of a ship occurs from one port to another, with a time of departure from a port of departure and a time of arrival at a destination ports being estimated so as to enable an overall sail time to be approximately determined. However, once a ship reaches a destination port a variety of factors may affect a time that the ship spends at that destination port; for example, skill of a pilot in guiding the ship into the destination port, congestion at the port, and unload and load speed at the port may each cause a mooring time of the ship to increase. As a result, a time used as a basis for a voyage of a ship between ports is subject to variance and a relay time for the ship to proceed may increase. In such a case, a time provided for further passage of the ship becomes shorter in proportion to the length of the delay at the destination (relay) port, and as a result a speed at which the ship must proceed from the destination (relay) port will need to be increased. If a speed of travel of the ship is increased an amount of fuel consumed over a set sailing distance also will increase.
Further, factors such as weather and marine conditions may also cause an increase in fuel consumption by the ship. A ship navigator determines a speed of travel of a ship between ports and performs a voyage by taking into account such conditions, but when an amount of fuel consumption required for a voyage differs from a planned or predicted amount of fuel consumption, a ship operation manager, a ship navigator or the like will wish to ascertain why a difference in planned or predicted fuel consumption has occurred.